Answer
${{\$}} 8500$ per month.
$2111$ hits per day
Work Step by Step
Quadratic models have the form:
$f(x)=ax^{2}+bx+c$
and their graph is a parabola.
The sign of $a$ determines which way the parabola opens.
This one opens down ($a\lt 0$).
$c$ gives us the y-intercept, $f(0)=c.$
The vertex $(-\displaystyle \frac{b}{2a}, f(-\frac{b}{2a}))$ is a maximum point.
So, the maximum volume occurs for
$x=-\displaystyle \frac{0.085}{-0.000005}={{\$}} 8500$ per month.
Thus, the maximum volume is $h(8500)\approx 2111$ hits per day
